Re: uvm_fault with -current XEN3_DOMU

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, May 16, 2008 at 02:01:25PM +0200, Christoph Egger wrote:
> On Friday 16 May 2008 12:53:49 Manuel Bouyer wrote:
> > On Fri, May 16, 2008 at 11:39:32AM +0200, Christoph Egger wrote:
> > > On Thursday 15 May 2008 10:18:15 Manuel Bouyer wrote:
> > > > On Thu, May 15, 2008 at 11:45:54AM +1200, Mark Davies wrote:
> > > > > Trying to run an i386 XEN3_DOMU kernel from this morning results in
> > > > > an immediate uvm_fault:
> > > > >
> > > > > green-mountain# xm create -c homepages
> > > > > Using config file "/etc/xen/homepages".
> > > > > Started domain homepages
> > > > >  MAC address 00:16:3e:00:00:11
> > > > > unknown type console at xenbus0 id 0 not configured
> > > > > uvm_fault(0xc04b1d00, 0, 1) -> 0xe
> > > > > kernel: supervisor trap page fault, code=0
> > > > > Stopped in pid 0.2 (system) at  0:      invalid address
> > > > > db> bt
> > > > > uvm_fault(0xc04b1d00, 0, 1) -> 0xe
> > > > > kernel: supervisor trap page fault, code=0
> > > > > Faulted in DDB; continuing...
> > > > > db>
> > > >
> > > > I've seen this too. It's probably calling a NULL function pointer.
> > > > I've not had a chance to look at this more closely yet.
> > > >
> > > >From a rough look into this, this seems to be an interrupt problem.
> > >
> > > The problem is not DomU specific. It also happens on Dom0 -current.
> >
> > in my case it seems to be because:
> > db> x/x x86_cpu_idle
> > netbsd:x86_cpu_idle:    0
> 
> On Dom0, I didn't have the chance to get into ddb as I got into an endless 
> loop of faults in ddb.
> 
> > The attached patch makes a domU kernel boot for me again. I'll commit it
> > this evening unless somone beats me.
> 
> I can confirm this makes dom0 boot again - with an workaround:
> cpu_identify(ci) works for the cpu but not the vcpu.
> the cpu identify code thinks, the vcpu is a 386 CPU and calls
> panic in x86/x86/identcpu.c, line 816.

It seems to work for me on a i386PAE domU:

vcpu0 at hypervisor0: (uniprocessor)
: Intel 686-class, 2327MHz, id 0x6fb
vcpu0: 64 page colors

Will try a amd64 domU ...

-- 
Manuel Bouyer, LIP6, Universite Paris VI.           
Manuel.Bouyer%lip6.fr@localhost
     NetBSD: 26 ans d'experience feront toujours la difference
--